The present inventions relate generally to rotary valve based fluid handling systems. More particularly, wash delivery systems that permit simultaneous washing of multiple output fluid paths from a rotary valve are described.
Recent advances in drug discovery have produced an overwhelming number of drug-like compounds to be tested for activity against protein targets. These drug-like compounds have various origins including natural products, and compounds produced through traditional organic syntheses and combinatorial syntheses. Typically, the drug-like compounds are archived in compound libraries at differing concentrations. Retrieval and dilution (e.g., normalization), of such compounds is generally performed with multiple precision metering devices attached to multiple distinct channels, with each channel being capable of independently performing a dilution. The precision metering devices are preferably capable of delivering very small (e.g. sub-microliter magnitude) precise amounts of the retrieved (and possibly diluted) compounds for testing.
In all liquid handling systems a cleansing of the fluid channels must be accomplished prior to the manipulation of the next compound. This cleansing can be achieved by washing the channels or, alternatively, by attaching a new disposable tip. Disposable tips are extremely expensive in the context of compound screening where an extensive library may contain as many as a million or more samples. Thus, washing the channels is generally preferred. However, the washing step can be a rate limiting factor in the liquid handling protocol. Accordingly, improved precision liquid handling systems that can incorporate simultaneous washing of a plurality of different fluid channels would be desirable.
To achieve the foregoing and other objectives, and in accordance with the purpose of the present invention, a wash system for a precision fluid handling system that permits simultaneous washing of a plurality of parallel fluid channels is disclosed. In one aspect of the invention, a specialized rotary wash valve is described. In another aspect of the invention a system that incorporates independent wash and selector valves which permits a plurality of separate fluid lines emerging from the selector valve to be washed simultaneously is described.
In one system aspect of the invention, independent wash and selector valves are utilized. The selector valve has a selector input port and a plurality of selector output ports. Each selector output port has an associated dispensing line. The selector valve has a number of different working positions which each make a fluidic connection between the selector input port and a particular one of the selector output ports. The wash valve has a wash fluid input port and a plurality of wash fluid output ports. Each wash output port has an associated wash line that is coupled to an associated dispensing line. In a first working position, the wash valve makes a fluidic connection between the wash fluid input port and the plurality of wash fluid output port. In a second working position the wash fluid input port is disconnected from the plurality of wash fluid output ports. With this arrangement, all of the dispensing lines may be washed in parallel by simply opening the wash valve.
In a preferred embodiment, both the wash valve and the selector valve are rotor based valves that have a rotor face plate that rotates relative to a stator face plate to make and decouple fluidic connections between their respective input and output ports.
In another aspect of the invention a unique rotary wash valve structure is described. In this embodiment the rotor face has a central recess and a multiplicity of angularly spaced grooves that extend radially outward from the central recess. The stator has a stator face that has a central passage that opens opposite the central recess of the rotor face and extends to the wash fluid input port. The stator also has a plurality of outer holes that each couple to an associated wash fluid output port. Each outer hole is aligned with an associated groove when the valve is disposed in a first position. The rotor face and stator are arranged such that when the valve is rotated to a second position, the outer holes do not have any fluidic connection with the grooves such that the outer holes are all substantially dead-headed at the rotor face. one embodiment, the only openings in the rotor face are the central recess and the multiplicity of grooves that extend radially outward from the central recess and the valve has just two operational positions.